Share your requests for new features, channels, etc. with the Roku team! Search keywords and add a kudo to an existing topic to show your support, or create a new topic if your suggestion isn't listed.
Thanks for letting us know about the issue that you are experiencing.
Is NBC the only channel that you observe this issue with?
Try removing the NBC channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the NBC channel back once more. Does this clear up the issue you are seeing?